Braking apparatus



M. LOUGHEAD BRAKTNG APPARATUS May 27 1924. lgl

Filednec. 17, 1926 ZagL raeaea any er, ieee..

narran stares earner carica..

MAIALM LOUGHEAD, DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO HYDRAULIC BRAKE COMPANY, 0F LOS ANGELES, CALIFORNIA, A. CORJPGRA.-

Tron or oALIroRNrA.

BEARING APPARATUS.

Application filed December 17, 1920.. Serial No. 431,334.

To all whom t may concern Be it known that l, MALCOLM LOUGHEAD, a citizen of the United States, and resident of Detroit, in the county of W'ayne and State of Michigan, have invented a certain new land useful Improvement in Braking Apparatus, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings,

l@ forming a part of this-specification.

My invention relates to braking apparatus of the fluid-operated type for automobiles and similar vehicles, and is concerned especially with improvements in a Huid compression device adapted for use in connection with apparatus of the kind mentioned which is operated by a foot pedal or other means forv supplying iiuid under pressure to the brake operating mechanism.

One of the objects of the present invention resides in the provision of pressure producing mechanism of the character described by means of which the fluid column is mani'pulated throughout the braking operation, Without causing a suction in the system which might effect the introduction of air bubbles at leaks occurring in the line, which would seriously impair the general e'ectiveness of the pressure mechanism.

the provision of a mechanism ofthe character described, which comprises a iiuid reservoir for relieving any suction which may be produced in the system, and for compensatmg for leakage at jointsithroughout thc system whereby a constant supply of operating iuid is maintained in the system.

A still further object resides in the provision of an improved compression device 4o wherein simultaneously operable high and low pressure producing means. are provided. A still further object resides in the provision of means controlled by the pressure in the system for disassociating the low pressure producing means from the system.

'The' foregoing and other objects of the present invention will appear as the follow- Another object of my invention consists in vof the device of my invention, the parts thereof being illustrated in their respective normal inoperative positions, and

Figure 3 is an isolated end View of the 60 re-filling -valve forming an element of the device (shown in Figure 2.

The same reference numerals designate the same parts throughout the views.

Referring to the. drawing, the compression device of my invention is designated generally by the reference numeral 4, and is adapted to bperate a pair of braking mechanisms 5-5, on the forward steering wheels, and a similar pair of braking mechanisms 5a- 5B on the rear wheels of the automobile. These braking mechanisms may be of 'any appropriate construction but preferably are of the character disclosed in my application Serial No. 431,332,1iled December 17, 1920, which has matured in'to'Patent No. 1,460,- 163, June 26, 1923. The device has cornmunication with both of the pairs of mechanisms through a piping system indicated generally by the reference numeral 4, The e0 system 4a, it will be noted, comprises a single pipe running the length of the chassis whlch supplies the communicating branches at the front and. rear of the chassis, preferably through swivel connections shown at @-43. While theseconnections may be of any suitable design and construction, I prefer to provide connections as illustrated in my application, Serial No. 431,335 tiled of even date herewith. l

Referring now particularly to Figure 2, it will be noted that my improved com ression device comprises a main casting 6, av

.ing an upwardly extending bracket 7,

Jormed integral therewith. Provided near th'e upper end oil the bracket is an integral, laterally projecting lug 8, which is securely held in a clamping collar provided on the bracket 9. rllhe bracket 9 is bolted or otherwise supported conveniently on the nether side of the toe board 10, which, as illustrated, extends at an angle of substantially o to the 'door 11.. llhile the device is illustrated as tilted at an angle of substantally 45 to the floor 11, and at right angles to the toe board 10, it will, of course, be apparent that this inclination is adjustable as desired by means of the clamping collar provided on the bracket 9.

The cylinder 12 forming a part of the main casting 6 extends upwardly in spaced parallel relation to the bracket 7 through a hole 13 in the toe board 10. rlhe bore 14 oi the cylinder12 is open at its upper end, and slidably receives a piston 15,` which projects a substantial distance above the toe board 10, and is provided at its outer end with a suitable foot pedal 16. rllhe piston 15 is provided with a concentric bore 17, which is closed at its ,upper end at the pedal 16 by means of a plug 18, and at its lower end has a downwardly working cup leather 19, secured thereto by means of a suitable bushing 20.

Slidable in the bore 17, and co-axial with the piston 15, which ll shall hereinafter refer to as the low pressure piston is a second piston 21, which will hereinafter be referred to as thelhigh pressure piston.

'llhe piston 21 is fixed in relation to the cylinder 12 and is provided with a longitudinal concentric bore 22, the upper end of which is slightly reduced to provide a shoulder 23. Secured to this end of thepiston 2l, by means of a ring 24, is an upwardly working cup leather 25. 'llhe ends oil the ring 24 are flanged as shown to engage at one end the shoulder 23, and at the other end the cup leather 25. rllhe piston 21 is enlarged at its lower end .as shown, and is threaded into the lower end of the bore 14 of the cylinder 12. A plug 26' closes the lower end of the bore 14 slightly be neath the lower end of the piston 21, to pro-- vide a substantial chamber 27 with which the bore 22 communicates. 'llhe lower end of the cylinder bore 14 isenlarged as shown to provide a chamber 28 above the enlarged lower end of the piston 21.

A shoulder 29 is provided on the cylinder 12 and a tension spring 30 surrounds the cylinder 12 and piston 15, and lies between the shoulder 29, and the pedal 16, tending to urge the piston 15 outwardly from the cylinder 12. A longitudinal slot 31 provided in the outer wall ofthe piston 15 cooperates with av set screw 32 to limit the reciprocal movement of the piston within the cylinder 12.

apeeaeai Formed integral with the casting 6 and parallel to the cylinder 12 are the eylindv 33 and 34. Provided adjacent the ends of the cylinder 33 are the valve seats 35 and 36, with which are arranged to co-operate valves 37 and 38, respectively. rll"he valves 37 and 38 are provided with stems 39 which are threaded at their outer ends to receive nuts 40l whereby the stems are secured to the valves. rlPhe opposite enlarged biturcated ends 41 of the stems 39 are joined/by means of a link 42 as shown. llt will be seen that the valves 37 and 38 are socoupled that when one of them is seated, the other is open. The open end ot the cylinder 33 is closed by a threaded plug 43. An adjusting screw 44 extends through the plug 43, and carries on its inner end a collar 45, to properly tension the spring 46, which urges the valve 37 to its seat. 'llo prevent leakage of fluid under pressure past the screw 44, packing material 47 is provided which maybe suitably compressed by a nut 48.\

The opposite end of the cylinder 33 is provided with a nipple 49 with which the outlet pipe 50 is connected by means of a union 51. 'llhe pipe 59 may be joined with the pressure responsive means of the brake operating mechanism in any desired manner but preferably as disclosed in my application, Serial No. 431,332 'above mentioned. A ytransverse passage 52 establishes communication between the chamber 27 and the cylinder 33 below the valve 38 and withY the pipe 50.

Provided adjacent the lower openv end of the cylinder 34 is a valve seat 53 with which co-operates a valve 54 which will4 hereinafter be referred to as the refilling valve. rll`he open endfof the cylinder 34 is closed by a threaded .plug 55.A A ten'sion spring 56 is disposed between the plug 55 and the valve 54, tending to hold the latter to its seat.

` rll`he end of the cylinder 34 opposite the plug is provided with an -externally threaded stem 57 which Ais provided with a central bore 58 .openinginto the cylinder 34. Connected to the stem 57 by means of a un'ion 59 is a pipe 60 which extends up.-

wardly to a fluid reservoir which may be located; upon the rear of the instrument board or any other convenient place. The interior of the reservoir is subject to atmospheric pressure.

A passage 61 extends transversely in the casting 6, over the passage 52 and parallel therewith.v andA establishes communication between the chamber .28 at the lower end of the cylinder 12 and the cylinder 33 between valves 37 and 38, and the cylinder 34. beneath the refilling valve 54. Another passage 62 joins the cylinders 33 and 34 at their upper ends.

lln order to permit easy steady movement incapaci of the valves 37, 38 and 54 within their respective cylinders, and in order not to unduly impede the passage of fluid thereby, I preferably forni these Valves with f'luted portions 63, beneath the heads as most clearly seen in Figure 3, and as a further precaution I provide openings as shown at 64, between the webs of the fluted portion 63, ad-

- jacent the valve head.

Before proceeding to a description of the operation of the mechanism just described, it may be noted that the spring 46 which tends to force ythe 'valve 37 to its seat, has preferably a tension sufficient to resist a pressure of approximately 20 pounds per square inch. However, the spring tension muy lie-Widely varied to accommodate givcn conditions. The spring 56 is very light, having sufhcient tension merely to hold the valve to its seat.

The. entire device is, of course, completely filled with the operating fluid which is preferably a noncompressible oil or alcohol although a compressible fluidas air may bc utilized. The fluid reservoir 65 previously mentioned is filled almost completely periodically, to compensate for the loss of oil throughout the system, due to leakage, evaporation, etc.

When the parts are in their respective normal inoperative positions, the piston 15 is substantially withdrawn from the cylinder 12, and the valves 37 and 54 are closed; the valve 38, however, being open. Pressure upon the pedal'16, communicated thereto by the operators foot, depresses the piston 15, which causes a flow of oil from the space about the piston 21 through passage 61, past the valve 38, into the pipe 50, and, simultaneously from the bore 17 through passage 52, also into the pipe 50. Continued depression of the pedal 16 causes the flow of oil along this circuit until all of the slack is taken up in the brake bands by the brake operating mechanism above referred to. I have found that |at this point the pressure in the system has reached approximately 20 pounds. The moment this pressure is attained, and depression of the pedal 16 is continued, the valve 37 is unseated against the tension of the spring 46. Simultaneously, with the opening of valve 37, the valve 38 is closed. The space above the valve 37 is connected to the reservoir which is subjected to atmospheric pressure. f The fluid under pressure in the cylinder 33 rushes past the head of the valve, thereby urging the same upwardly and assisting the valve 38 to seat quickly. Furthermore, the pressure beneath the valve 38. assists the very prompt closing of this valve and holds it closed as long as the pressure is maintained. As the depression of the pedal 16 is continucd, a very great increase of pressure in the system results, since the same is subject solely to the pressure produced by the high pressure piston, the bore of which, it will be noted', is very small, to permit a broader range of movement of the pedal and at the same time to permit of a greater range of production of pressure in the system. Simultaneously with the production of the high pressure in the pipe 50 by the high pressure piston, the low pressure piston is causing a flow of oil through the passage 61 past the valve 37 through passage 62 into cylinder 34, out through the pipe 60 and upwardly into the fluid reservoir 65. By the time the low pressure piston reaches the vicinity of the chamber 28, the pressure existing in the system produced by the high pressure piston is very high, so high, in fact, that I have found I am enabled to stop a vehicle in a much shorter distance than it has heretofore been possible. When it is desired to relieve the braking pressure in the system, the operator simply removes his foot from the pedal 16. As there is no measurable amount of compression in the fluid in the system, it is necessary to provide spring means at various points to insure the easy and rapid return of the pants to their respective normal inoperative positions. In this connection the spring 30 is provided to urge the pedal 16 outwardly. A rather considerable head is produced by the fluid which has been forced into the fluid reservoir by the low pressure piston, as above described. As the low pressure piston recedes, this fluid is returned to the system through ,the refille ing valve 54 which is, unseated bylthe greater pressure existing on the upper side thereof. When the pressure in the system has been reduced to approximately 20 pounds per square inch. the valve 37 Will be urged to its seat, thereby opening the valve 38. As the low pressure piston recedes further. fluid passing through the passage 61 past the valve 38 and passage 52 into the chamber 27 and thence into the bore 22 completely fills the opening in the bore 17 above the high pressure piston. In a like manner, fluid passing the valve 38 into the passage 61 and past the refilling valve 54 into pas-l sage 61 and Athence into the bore 14 of the cylinder 12 completely fills the annular space beneath the low pressure piston. The

' sponsive to do not limit' myselie to these speciiic details, but claim further all adaptations and modications coming within the spirit and scope of the appended claims.

What l claim is:

l. ln a braking system for vehicles, brake members, a iluid pressure system, means rethe pressure therein or operating said brake members, and means for creating pressure in said system comprising a pressure producing means, a low pressure producing means, an outlet for the uid under pressure to said system, and means automatically actuated upon the duid being subjected to a predetermined pressure for closing communication between said 'outlet and said low pressure producing means.

2. ln a braking system for vehicles, brake members, a l'luid pressure system, means responsive to the pressure therein for operating said brake members, means for providing Huid under pressure, an outlet for the duid under pressure, said pressure providing means comprising a high. pressure producing means continually 1n communication with said outlet, a low pressure producing means normally in communication with said outlet, a valve forclosing the communica tion between said low pressure producing means and said outlet, and means actuated incident to subjecting said fluid toia redetermined pressure for moving said va ve to 3. lin a braking system for vehicles, brake members, a fluid pressure system, means re sponslve to the pressure therein for operating closed position.

i said brake members,`means forprovidingfluid under pressure, an outlet for the Fluid under pressure, said pressure providing means comprising a high pressure producing means arranged to torce a small volume of fluid into said outlet under high pressure, alow pressure producing means arranged to force a large volume of fluid into said system under low pressure, said high and low pressure producing means being arranged to both force iluid into said outlet upon initial operation, and means operable at a predetermined pressure produced in said outlet for closing communication between said outlet and said low pressure producing means.

4r. ln a braking system for vehicles, brake members, a fluid pressure system, means re' sponsive to the pressure therein for operating said brake members, and means for creating pressure in said system comprising a high pressure producing means, a low pressure producing means, an outlet for the duid under pressure, said low pressure producing means being normally in communication with-said outlet, said high and low pressure producin means being arranged upon initial operation to both torce l'luid into said outlet, and valves operable at a pre- ,senesi determined pressure produced in said outlet for closing communication between said outlet and said low pressure producing means, but maintaining communication between said high pressure producing means and said outlet.

5. ln a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said bralre members, means for providing iluid under pressure, an outlet for the duid under pressure, said pressure providing means comprising means for initially injecting a large volume oi fluid into said outlet under low pressure, means operable only at a predetermined pressure produced in said outlet ior closing communication between vsaid outlet and said means lor initially injecting, and means lor thereafter injecting a small volume of luidinto said outlet under a high pressure.

"6. lin a braking system lor vehicles, brake members, a fluid pressure system, means re sponsive to the pressure therein for oprating said brake members, means for providu ing fluid under pressure, an outlet Ylor said iluid under pressure, said pressure provid ing means comprising a high. pressure ducing means arranged 'orcin volume of uid into said outlet uno pressure, a low pressure produci arranged to force a relatively large of fluid into said outlet under a i tively low pressure, a i f. high and low pressure producing mee` ing arranged upon initial operation to force luid into said outlet, means operate.'v by a predetermined pressure produced in said outlet for closing communication between said outlet and said low pressure producing means and placing said low pressure producing means in communication with said duid reservoir, whereby said hi 't pressure producing means is alone main tainedfin communication with said outlet, and means operable upon reduction of pres-- sure in said outlet for providing communication between said reservoir and said hi and low pressure producing means where#J luid from said reservoir is caused to re enter the ressure producing means.

7. ln a raking system igor vehicles, braliaf; members, a Jlluid pressure system, means responsive to the pressure therein lor operating said brake members, and means r' creating pressure in said system comprisn a high pressure producing means, pressure producing means, an outlet 'lo `fluid under pressure, said high low pressure producing means being arranged upon initial operation to both force uid ir.- to said outlet, a duid reservoir, and means actuated by a predetermined pressure in said outlet for closing communication said low pressure producing means Maasai outlet and opening communication between lid said low pressure producing means and said Huid reservoir. n

8. In a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said brake members, means for providing a iuid under pressure, an outlet for the fluid under pressure, said pressure providing means comprising a high pressure cylinder arranged to have constant communication with said outlet, a low pressure cylinder arranged to normally have communication with said outlet, pistons in said cylinders, a duid reservoir,.means for causing relative movement of said pistons and cylinders, means, operable at a predetermined pressure produced in said system for opening communication between said iuid reservoir and said low pressure cylinder and for closing communication therebetween and said outlet, com rising a pair of valves so connected that w en'one is seated, the other is ofi its seat, said valves being also operated by a predetermined difference in pressure between the duid reservoir and said outlet to establish communication between said reservoir and said hi h and low pressure cylinders for replenis ing the supply of duid in said cylinders after operation. i

9 In a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said brake members, means for providing Huid under pressure, an outlet for said fluid under pressure, said pressure providing means comprising a high pressure cylin er arranged to have constant communication with said outlet, a low pressure cylinder arranged to normally have communication with said outlet, pistons in said cylinders, means for causing said pistons to enter said cylinders simultaneously to force the luid from said cylinders, a fluid reservoir, a pair of valves controlled by the pressure in said outlet, said valves being so arranged that when one is seated the other is olf its seat, one of said valves serving to establish communication between the said low pressure cylinder and said uid reservoir, the other of said valves serving to limit the communication of the high pressure cylinder to said outlet. v

l0. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a uid pressure system and means responsive to the pressure therein for operating said brake members, a device for creating plressure. in said system com rising a ig pressure producing means, a ow pressure producing means an means responsive topredetermined pressures in said system for opening and closing communication between said system and said low pressure producing means.

the wheels, a

11. In a braking system for vehicles, brake members for eng ng the brake drums of uail pressure system and means responsive to t e pressure therein for operating said brake members, a device for creating pressure in said system comprising a high pressure producing means continually in communication with said system, a low pressure producing means normally in communication with said system, and means operable at a predetermined pressure in said system for cutting off said low pressure producing means from communication with said s stem.

12. n a braking system for vehicles, brake members for en aging the brake drums of the wheels, a uid pressure system and means responsive to the pressure therein for operating said brake members, a device for creating pressure in said system .comprising a high pressure producing means arranged to force a smal volume of duid into said system, under high pressure, a low pressure producing means arran ed to force a large volume of duid into sai s stem under low pressure, said high and ow pressure producing means being arranged upon initia operation to both force duid into said system, and a pair of mechanically connected valves operable at a predetermined pressure in said system for closin communication between said systeml an said low pressure producing means, and limiting communication of the high pressure producing means to said system.

13. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a uld pressure system and means responsive to the pressure therein for operating said brake members, a device for creating pressure in said system comprisin means for initially injecting a large vo ume of Huid into said system, means operable by a predetermined pressurel in said system for closing communication between said system and said firstmentioned means, and means for thereafter injecting a small volume of fluid under high pressure into said system.

14. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a Huid pressure system and means responsive to the pressure therein for operating said brake members, a device for creating pressure in said system comprisin a hlgh pressure producing means arran e to force a small volume of fluid into sai system under a high pressure, a low pressure producing means arranged to force a comparatively large volume of fluid into said system under a relatively low pressure, said high and low pressureproducing means bein arran ed upon initial operation to both orce Huid into said system, a iuid reservoir, means operable by a predetermined pressure produced in said system for closing communication between said system and said low pressure producing means and opening communication between said low pressure producing means and said fluid reservoir, whereby said high pressure producing means is alone maintained in communication with said system,y

and means operable upon the reduction of pressure in said system for establishing communication between said duid reservoir and said high and low pressure producing means,

operating said brake members, and means for creating pressure in said system comprising a cylinder, a piston member within said -cylinder spaced therefrom and secured thereto, said piston member being provided with an opening extending longitudinally thereof, a second cylinder arranged to slide in the space between said first-mentioned cylinder and said piston member and itself forming a piston, fluid within all the openings and spaces within the said cylinders and piston, means for causing movement of said second cylinder relative to said firstmentioned cylinder and piston member carried thereby, whereby said fluid is forced from said cylinders under pressure, an outlet for said fluid, a passage continually connecting said opening to said outlet, a second assage normally connecting said space to said outlet and means operated by a predetermined pressure in said passages and said outlet for closing the connection of said second passage to said outlet. N

16. lln a braking system for vehicles, brake members, a lluid pressure system, means responsive to the pressure therein for operating said brake members, and means for creating pressure in said system, comprising a cylinder, a piston member within said cylinder spaced therefrom and secured thereto, said piston member having an opening extending longitudinally thereof, a second cylinder arranged to slide in the space between said first-mentioned cylinder and said piston member anditself forming a piston, fluid within all the openings and spaces within the said cylinders and piston, means for causing movement of said second cylinder relative to said first-mentioned cylinder and pistonmember carried thereby, whereby said duid is forced from said cylinders under pressure, an outlet for said fluid, apassage continuallyconnecting said opening to said outlet, a second passage normally connecting said space to said outlet, a fluid reservoir and means operated by' apredetermined pressure 'in said pasincassi sages and said outlet for closing the con;- nection of said passage to said outlet, and joining said second passage to said fluid reservoir.

17. lln a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said brake members, and means for creating pressure in said .system com prising a cylinder, a piston member within said cylinder spaced therefrom and secured thereto, said piston member being provided with an opening extending longitudinally thereof, a second cylinder arranged to sli `e in the space between said first-mentioned cylinder and said piston member and itself forming a piston, fluid within all the openings and spaces within the said cylinders and pistons, means for causing movement of said last-mentioned cylinder relative to said first mentioned cylinder andpiston member carried thereby, whereby said fluid is forced fromsaid cylinders under pressure,

an outlet for said fluid, a passage continually connecting said opening to lsaid outlgt', f a secondpassage normally connecting said' space to said outlet, a duid reservoir, and a pair of valves operated by apredetermined pressure in said passages and said outlet for closing the connection of said second passage to said outlet, and joining it to said fluid reservoir.

18. ln ay braking system Vfor vehicles, brake members, a fluid pressure system,

means responsive to the pressure therein for operating said brake members, and means for creating pressure in said system cornprising a cylinder, a piston member concenf trically arranged within said cylinder spaced therefrom and secured' thereto, said piston member being provided with an opening extending longitudinally thereof, a second cylinder arranged to slide in the annular space between said first-mentioned cylinder and said piston member and itself n forming a piston, duid within all the open= ings and spaces within the said cylinders' and pistons, means for causing movement of said second cylinder relative to said Amentioned cylinder and piston member carried thereby, whereby said fluid is forced from said cylinders under pressure, an cui@ let for said duid, a `passage continually conn necting said opening to said outlet, a sec ond passage normally connecting said an nular space to said outlet, a duid reservoir, and a pair of valves operated by a predetermined pressure in said passages and said outlet for closing the connection of said sec-1 ond passage to said outlet and joining T11 to said fluid reservoir.

y19. lin a braking -system for vehicles, brake members for engaging the brake drums of the wheels, a duid pressure s stem, means responsive to the pressure there in for operating said 'brake members, a. deabove and belowl a, predetermined pressure vice forcreating pressure in said system in the system. f

comprising e high pressure producin In Witness whereof, if hereunto subscribe means, a 10W pressure producing means, en my name this 13th dey of December, 1920.

e a valve for openin and closing oommuni- MALCOLM LOUGHED. i cation between sai system and said low Witnesses:

pressure producing means,1 said valve being l. 0. BURTON, actuated responsive to 'changes in pressure l H. Mower. 

